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Technical Topics => Equipment => Topic started by: bandarr3000 on August 16, 2019, 2005 UTC

Title: Isolator Frequency Range
Post by: bandarr3000 on August 16, 2019, 2005 UTC

OK, stupid question time. If I have an 1.8-30MHz isolator on my multiband antenna (80m-6m), should I still be able to transmit 6m?

Title: Re: Isolator Frequency Range
Post by: Josh on August 16, 2019, 2138 UTC

If you're talking about a line isolator and not a lowpass filter, yes. If you had a lowpass filter with a cutoff above 6m yes in that case too. If you had a lowpass filter below 6m cutoff obviously no.

Title: Re: Isolator Frequency Range
Post by: bandarr3000 on August 20, 2019, 0332 UTC

Quote from: Josh on August 16, 2019, 2138 UTC

If you're talking about a line isolator and not a lowpass filter, yes. If you had a lowpass filter with a cutoff above 6m yes in that case too. If you had a lowpass filter below 6m cutoff obviously no.

Thank you!

Title: Re: Isolator Frequency Range
Post by: Josh on August 20, 2019, 1714 UTC

More to the point, isolators simply choke off the rf flowing on the outside of the coax and have no effect on whatever rf is flowing inside that coax. Isolators are also often frequency dependent insofar as their maximum effectiveness goes.
Some that work spectacularly at hf fail at vhf and above, those mixed for best response at vhf and above are seldom useful at hf. I've mixed isolator ferrites for a broader response, for example, using 43 mix as well as type 6 and/or type 4.